U.S. patent application number 10/642887 was filed with the patent office on 2005-02-24 for automotive lighting system.
This patent application is currently assigned to Visteon Global Technologies, Inc.. Invention is credited to Sayers, Edwin Mitchell.
Application Number | 20050041433 10/642887 |
Document ID | / |
Family ID | 34193742 |
Filed Date | 2005-02-24 |
United States Patent
Application |
20050041433 |
Kind Code |
A1 |
Sayers, Edwin Mitchell |
February 24, 2005 |
Automotive lighting system
Abstract
The present invention is an automotive lighting system including
semiconductor laser sources, optical waveguides, and focusing
assemblies for generating, transmitting, and directing light for a
variety of automotive applications. In particular, the present
invention includes phosphor-based semiconductor lasers integrated
into an automotive lighting system that is usable for producing
white light in close proximity to a focusing assembly, or remotely
from the focusing assembly through a network of optical waveguides
in a distributive lighting system.
Inventors: |
Sayers, Edwin Mitchell;
(Saline, MI) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE/CHICAGO/COOK
PO BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
Visteon Global Technologies,
Inc.
|
Family ID: |
34193742 |
Appl. No.: |
10/642887 |
Filed: |
August 18, 2003 |
Current U.S.
Class: |
362/459 |
Current CPC
Class: |
H01S 5/4093 20130101;
F21Y 2113/17 20160801; H01S 5/0225 20210101; H01S 5/02257 20210101;
H01S 5/4043 20130101; B60Q 1/0011 20130101; F21S 43/235 20180101;
G02B 6/0006 20130101; H01S 5/0087 20210101; F21S 41/24 20180101;
F21K 9/00 20130101 |
Class at
Publication: |
362/459 |
International
Class: |
B60Q 001/00 |
Claims
1. An automotive lighting system comprising: a semiconductor laser
light source adapted to emit laser light of at least one
wavelength; an optical wave guide coupled to the semiconductor
laser light source to guide and blend the laser light; and a
focusing assembly coupled to the optical wave guide to direct the
laser light.
2. The automotive lighting system of claim 1 wherein the
semiconductor laser light source is an epitaxial structure
including two light-emitting layers, the two-light emitting layers
emitting light of distinct frequencies.
3. The automotive lighting system of claim 2 wherein the two
light-emitting layers are gain-guided waveguides.
4. The automotive lighting system of claim 2 wherein the two
light-emitting layers are index-guided waveguides.
5. The automotive lighting system of claim 2 wherein a first of the
two light-emitting layers emits light corresponding to a red
wavelength, and further wherein a second of the two light-emitting
layers emits light corresponding to a blue-green (Cyan)
wavelength.
6. The automotive lighting system of claim 2 wherein a first of the
two light-emitting layers emits light corresponding to a yellow
wavelength, and further wherein a second of the two light-emitting
layers emits light corresponding to a blue wavelength.
7. The automotive lighting system of claim 1 wherein the
semiconductor laser light source is an epitaxial structure
including three light-emitting layers, the three-light emitting
layers emitting light of distinct frequencies.
8. The automotive lighting system of claim 7 wherein the three
light-emitting layers are gain-guided waveguides.
9. The automotive lighting system of claim 7 wherein the three
light-emitting layers are index-guided waveguides.
10. The automotive lighting system of claim 7 wherein a first of
the three light-emitting layers emits light corresponding to a red
wavelength, and further wherein a second of the three
light-emitting layers emits light corresponding to a green
wavelength, and further wherein a third of the three light-emitting
layers emits light corresponding to a blue wavelength.
11. A light source for use in an automobile comprising: a
semiconductor laser defining an emitting surface and adapted to
emit laser light of a predetermined wavelength; a phosphor layer
coupled to the emitting surface of the semiconductor laser such
that laser light emitted from the semiconductor layer causes
phosphorescence in the phosphor layer, and further such that light
including a plurality of frequencies is emitted from the phosphor
layer.
12. The light source of claim 11 wherein the semiconductor laser
emits laser light corresponding to a blue wavelength.
13. The laser light source of claim 11 wherein the semiconductor
laser emits laser light corresponding to an ultraviolet
wavelength.
14. The laser light source of claim 11 wherein the phosphor layer
is a tri-color phosphor.
15. The laser light source of claim 11 wherein the semiconductor
laser emits laser light corresponding to an ultraviolet wavelength,
and further wherein the phosphor layer is a tri-color phosphor such
that in response to being irradiated by the semiconductor laser,
the tri-color phosphor emits substantially white light.
16. A remote lighting system comprising: a first semiconductor
laser emitting laser light of at least one selected wavelength; a
first network of optical waveguides coupled to the semiconductor
laser light source to guide and blend the laser light; and a
focusing assembly coupled to the optical wave guide to direct the
laser light, the focusing assembly disposed remotely from the
plurality of semiconductor laser light sources.
17. The remote lighting system of claim 16 further comprising a
second semiconductor laser emitting laser light of a second
selected wavelength.
18. The remote lighting system of claim 16 wherein the first
network of optical waveguides is a bundle of fiber optic
channels.
19. The remote lighting system of claim 16 further comprising a
second semiconductor laser emitting laser light of a second
selected wavelength wherein the second semiconductor laser is
coupled to a second network of optical waveguides, and further
wherein the first network of optical waveguides and the second
network of optical waveguides are severally coupled to the focusing
assembly such that laser light of distinct frequencies is blended
in the focusing assembly.
20. The remote lighting system of claim 16 wherein the focusing
assembly includes headlamps, taillights, turn signals, and interior
lighting for an automotive vehicle.
21. The remote lighting system of claim 16 wherein the focusing
assembly includes an optic, and further wherein the optic comprises
an aspherical section.
22. The remote lighting system of claim 16 wherein the focusing
assembly includes an optic, and further wherein the optic comprises
a substantially smooth surface having alternating straight and
annular portions.
23. The remote lighting system of claim 16 further comprising an
array of semiconductor lasers coupled to at least the first network
of optical waveguides, the array of semiconductor lasers including
at least the first semiconductor laser.
Description
BACKGROUND
Technical Field
[0001] The present invention pertains to the field of illumination,
and more particularly to lighting systems for automotive
vehicles.
BRIEF SUMMARY
[0002] Numerous efforts have been made to increase the safety,
reliability and efficiency of motor vehicles and aircraft while
reducing the overall cost of manufacturing. Essential to meeting
these goals is incorporating new and expanding technologies into
the manufacturing process and the vehicle itself. Optical
technology has offered many benefits by providing more efficient
and more reliable light sources than were previously available.
Specifically, efforts have been made to provide alternative
lighting systems, which substantially reduce the number of light
sources in vehicle lighting systems. These systems reduce the
vehicle's electrical load and thereby providing a power budget for
other vehicle features. Styling may also be differentiated through
the use of systems that enable different appearances and packages.
Suitable alternative light sources include solid state lasers, also
known as laser diodes or semiconductor lasers.
[0003] Illuminating devices of the above-mentioned general type are
known in the art. A representative illuminating device has several
semiconductor light sources in the form of light diodes. The light
diodes may be three-phase light diodes which, depending on
electrical control and configuration can emit light in at least two
different colors. With this illuminating device it is possible to
emit light with at least two different wavelength bands (evidenced
by differing color), and all light diodes emit light of the same
color. With such a construction the illuminating device can be used
for different illuminating and signaling functions. Utilization of
this illuminating device within a headlamp is complicated since the
light diodes do not emit white light, but instead they emit red,
green and blue light, which must be modulated in such a way as to
blend the light over time, switching colors faster than the eye
response. Moreover, the three-phase light diodes are more expensive
than simple semiconductor light sources, which emit light of one
color. Also, the control of the three-phase light diodes requires a
higher expense so that this illuminating device is expensive in
both its manufacture and operation.
[0004] Other alternative lighting systems have incorporated an
array of semiconductor lasers that emit light of different
wavelengths. The light emitted from the array is blended and
directed by systems of optical fibers or other optical components.
While this type of system can provide generally white light, it
presents an inefficient means for mixing the distinct colors of the
semiconductor laser array. As such, there is a need in the art for
an inexpensive and easy-to-operate lighting system that improves
upon the benefits of laser diode technology.
[0005] Accordingly, the present invention is an automotive lighting
system including semiconductor laser sources, optical waveguides,
and focusing assemblies for generating, transmitting, and directing
light for a variety of automotive applications.
[0006] In particular, the present invention includes semiconductor
laser sources that may be laser diodes generating a single
wavelength of laser light. Alternatively, the present invention
includes epitaxial semiconductor structures that incorporate at
least two separate laser diodes in close proximity for generating
substantially white light from a single structure. Also described
are phosphor-based laser sources that include a semiconductor laser
source having a phosphor layer deposited in the direction of
propagation, thereby generating white light through
phosphorescence.
[0007] The optical waveguides include optical fibers and optical
fiber bundles, and the terms may be used interchangeably herein.
The optical waveguides may be coupled directly to a single laser
source emanating a single-color laser, to a single laser source
emanating a multi-color laser, or to a phosphor-based source that
emanates white light. The optical waveguides allow for great
flexibility in packaging the lighting system in an automobile, as
the light source may be located remotely from the focusing
assembly. For example, an array of semiconductor lasers can be
disposed in a remote location, for example in the engine
compartment, and the optical waveguides can transmit light from the
lasers to the headlamps and the taillights of the vehicle.
[0008] The focusing assembly includes various optical components
such as reflectors, refractors, lenses and filters that may be used
to adjust the color, intensity, and direction of the light passing
into and from the optical waveguides. In one embodiment, the
focusing assembly may be headlamp optical components designed so as
to fulfill the low-beam parameters set forth by the Society of
Automotive Engineers (SAE).
[0009] These and numerous other features and advantages of the
present invention are made more apparent through the detailed
description of the preferred embodiment which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic representation of an automotive
lighting system including an epitaxial semiconductor laser emitting
three wavelengths in accordance with one embodiment of the present
invention.
[0011] FIG. 2 is a perspective view of an epitaxial semiconductor
laser emitting two wavelengths in accordance with one embodiment of
the present invention.
[0012] FIG. 3 is a perspective view of a single-wavelength
phosphor-based laser source for emitting light at the semiconductor
junction in accordance with one embodiment of the present
invention.
[0013] FIG. 4 is a perspective view of a single wavelength
phosphor-based surface-emitting laser source in accordance with one
embodiment of the present invention.
[0014] FIG. 5 is a perspective view of a laser source coupled to a
shaped optic in accordance with one embodiment of the present
invention.
[0015] FIG. 6 is a perspective view of a laser source coupled to a
second shaped optic in accordance with an alternative embodiment of
the present invention.
[0016] FIG. 7 is a schematic view of an automotive vehicle
incorporating the automotive lighting system of the present
invention.
DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED
EMBODIMENTS
[0017] The following description pertains to an improved automotive
lighting system including semiconductor laser sources, optical
waveguides, and focusing assemblies for generating, transmitting,
and directing light for a variety of automotive applications.
[0018] Referring to FIG. 1, a schematic view of the automotive
lighting system 10 of the present invention is shown. A
semiconductor laser 12 emits laser light into an optical waveguide
28 which transmits the light to a focusing assembly 32, shown here
for example as a lens. The semiconductor laser 12 emits light of
distinct frequencies, which is blended and transmitted by the
optical waveguide 28, which directs the light to the focusing
assembly 32 for automotive application.
[0019] As shown, the semiconductor laser 12 is an epitaxial
structure, which consists of multiple layers having distinct
semiconductive properties. A series of inert layers 14 alternates
with active layers, including a first layer 16, a second layer 18,
and a third layer 20. The first, second, and third layers 16, 18,
20 themselves may consist of more than one semiconductor layer and
form a laser diode.
[0020] In one embodiment, the first layer 16 emits, for example,
red laser light 22. The second layer 18 may emit green laser light
24, and the third layer 20 may emit blue laser light 26.
Accordingly, the semiconductor laser 12 shown in FIG. 1 includes
three separate laser sources that are fabricated into one epitaxial
structure. The semiconductor laser 12 is specifically designed such
that the inert layers 14 are of minimal thickness such that the
first, second, and third layers 16, 18, 20 are optically
indiscernible from each other, a feature that increases the
efficiency and consistency of the light mixing.
[0021] In one embodiment, the inert layers 14 are materials having
a lower index of refraction relative to the first, second, and
third layers 16, 18, 20, thereby creating an index-guided epitaxial
semiconductor laser 12. Alternatively, the inert layers 14 are a
non-gain medium such that the laser gains are isolated to the
first, second, and third layer 16, 18, 20, a gain guided epitaxial
structure. As noted, the inert layers 14 are of minimal thickness
to ensure that the red laser light 22, the green laser light 26,
and the blue laser light 28 near the emitting surface of the
semiconductor laser 12.
[0022] The semiconductor laser 12 is coupled to an optical
waveguide 28, such as an optical fiber or an optical fiber bundle.
The optical waveguide 28 serves multiple purposes, most notably the
transmission of the laser light to the focusing assembly 32. In one
embodiment, red laser light 22, green laser light 24, and blue
laser light 26 are all channeled into the optical waveguide 28
wherein the respective laser colors blend into a white light 30
that is emitted from the optical waveguide 28. Alternatively, each
of the red laser light 22, green laser light 24, and blue laser
light 26 could be directed into a separate optical waveguide 28,
for example, as part of an optical fiber bundle. In the latter
example, the distinct colors are blended after transmission through
the optical waveguide 28.
[0023] As shown in FIG. 2, a second embodiment of the semiconductor
laser 34 is a bi-color epitaxial semiconductor laser is shown
separate from the waveguide with which it will be used. As
described above, a series of inert layers 36 bound each of a first
layer 38 and a second layer 40. In one embodiment, the first layer
38 emits laser light 42 that is red and the second layer 40 emits
laser light 44 that is blue-green or Cyan. In another embodiment,
the first layer 38 emits laser light that is yellow and the second
layer 40 emits laser light 44 that is blue.
[0024] As noted above, the inert layers 36 may be materials having
a lower index of refraction relative to the first and second layers
38, 40 thereby creating an index-guided epitaxial semiconductor
laser 34. Alternatively, the inert layers 36 are a non-gain medium
such that the laser gains are isolated to the first and second
layers 38, 40, a gain guided epitaxial structure. As before, the
inert layers 36 are of minimal thickness to ensure that the
respective laser light 42, 44 emitted by the semiconductor laser 34
is readily blended.
[0025] FIG. 3 is a perspective view of a preferred semiconductor
laser 46 for use in the automotive lighting system of the present
invention according to a third embodiment, also illustrated
separate from a waveguide with which it would be used. The
semiconductor laser 46 is a phosphor-based light source including
an active layer 50 disposed between a pair of inert layers 48. The
active layer 50 may be comprised of more than one layer, as is
typical of laser diodes.
[0026] The semiconductor laser 46 emits light (not shown) parallel
to the junction of the active layer 50 and the inert layers 48. The
active layer 50 emits blue laser light or, alternatively,
ultraviolet (UV) laser light. A phosphor layer 52 is deposited on
the edge of the semiconductor laser 46 such that laser light
emitted from the semiconductor laser 46 must interact with the
phosphor layer 52. The interaction, phosphorescence, produces a
substantially white light 54 suitable for a host of
applications.
[0027] The phosphor layer 52 material depends upon the wavelength
of light emitted by the active layer 50. If the active layer 50
emits blue light, then the phosphor layer 52 would be selected to
emit a substantially yellow-orange broad-band light when excited.
The combination of the blue light from the active layer 50 and the
yellow-orange light from the phosphor layer 52 would produce a
white light 54.
[0028] Alternatively, if the active layer 50 emits UV laser light,
then the phosphor layer 52 would be selected such that it is a
tri-color phosphor, emitting red, green, and blue light when
excited. The UV laser light from the active layer 50 acts as a pump
to stimulate the emission of red, green, and blue light from the
phosphor layer 52. The combination of the red, green, and blue
light produces a white light 54.
[0029] FIG. 4 is a perspective view of a surface-emitting
semiconductor laser 56 in accordance with another preferred
embodiment of the present invention. The semiconductor laser 56 is
a phosphor-based light source including an active layer 60 disposed
on an inert layer 58, such as a substrate. The active layer 60 may
be comprised of more than one layer, as is typical of laser
diodes.
[0030] The semiconductor laser 56 emits light (not shown) along a
direction normal to the surface of the active layer 60, as is known
for surface-emitting laser diodes. The active layer 60 emits either
blue laser light or UV laser light, as needed by application. A
phosphor layer 62 is deposited on the surface of the active layer
60 such that light emitted from the active layer 60 must interact
with the phosphor layer 62. The phosphorescent interaction produces
a substantially white light 64 suitable for a host of automotive
applications.
[0031] As before, the phosphor layer 62 material depends upon the
wavelength of light emitted by the active layer 60. If the active
layer 60 emits blue light, then the phosphor layer 62 would be
selected to emit a substantially yellow light when excited.
Alternatively, if the active layer 60 emits UV laser light, then
the phosphor layer 62 would be selected such that it is a tri-color
phosphor, emitting red, green, and blue light when excited. In both
instances, the net result is a color combination that creates white
light 64.
[0032] In accordance with alternative embodiments of the present
invention as described above, it may be advantageous to implement a
shaped optic for distributing and focusing the laser light. In
preferred embodiments, the optic may be shaped for large scale beam
focusing, or alternatively, the optic may be a smooth lens with
fine-grade surface features that better distribute the laser
light.
[0033] For example, FIG. 5 is illustrative of an embodiment in
which the laser source 46 emits white light 54 in the direction of
a shaped optic 55. In the particular embodiment shown, the optic 55
is an asphere. In a preferred embodiment, the optic 55 is an
asphere of several different sections so as to produce a desired
beam pattern, such as the SAE low beam pattern.
[0034] In FIG. 6, the optic 57 shown is a portion of a smooth lens
having fine-grade surface features. In this example, the optic 57
has alternating straight and annular surfaces that cooperate to
produce the desired beam pattern, such as the SAE low beam
pattern.
[0035] Each of the optics 55, 57 shown in FIGS. 5 and 6 are readily
adaptable for use in the automotive lighting system 10 shown in
FIG. 1.
[0036] The automotive lighting system 10 shown in FIG. 1 and
further described in FIGS. 2 through 6 can be integrated into an
automotive vehicle to create a remote lighting system (RLS).
[0037] FIG. 7 is a schematic view of such a remote lighting system
70 integrated into an automotive vehicle 72. The remote lighting
system 70 includes a light generator 74 incorporating at least one
semiconductor light source, generally designated as 90, as
described above in FIGS. 1-4. The light generator 74 is coupled to
a network of optical waveguides 76a, 76b, 76c, 76d, 76e that
collect, direct, and transmit laser light from the light bank 74 to
focusing assemblies of the automotive vehicle 72, as described
further herein.
[0038] For example, in order to provide forward lighting the light
generator is coupled to optical waveguides 76a, 76b which are
directed towards the forward portion 75 of the automotive vehicle
72. Optical waveguide 76a is coupled, for example, to a headlight
82a and/or a turn signal 84a. Similarly, optical waveguide 76b is
coupled, for example, to a headlight 82b and/or a turn signal
84b.
[0039] To provide rear lighting, optical waveguides 76c, 76d are
directed towards the rearward portion 77 of the automotive vehicle
72. As an example, optical waveguide 76c is coupled to a turn
signal 86a and/or a taillight 88a, and optical waveguide 76d is
coupled to a turn signal 86b and/or a taillight 88b. Optical
waveguides 76a, 76b may also be coupled to brake light assemblies
(not shown), that may be located at various positions in the
rearward portion 77 of the automotive vehicle 72.
[0040] Interior lighting is provided to the passenger compartment
78 of the automotive vehicle 72 via optical waveguide 76e. For
example, optical waveguide 76e may be coupled to an instrument
panel 80 located within the passenger compartment 78. In further
embodiments, the optical waveguide 76e may be coupled to a number
of lighting subsystems within the passenger compartment 78, such as
ambient lighting and warning lights.
[0041] In its preferred embodiments, the remote lighting system 70
includes a light bank 74 that contains an array 92 or system of
semiconductor lasers. Most preferably, the semiconductor lasers are
selected from a group of the phosphor-based lasers described herein
with reference to FIGS. 3 and 4. In order to provide superior
lighting quality, the semiconductor laser 56 of FIG. 4 emitting UV
light into a tri-color phosphor layer 62 provides consistent and
pure white light 64 for use in a multitude of automotive lighting
applications.
[0042] As described, the present invention is an automotive
lighting system including semiconductor laser sources, optical
waveguides, and focusing assemblies for generating, transmitting,
and directing light for a variety of automotive applications.
Although the present invention has been described with reference to
certain preferred embodiments, it is understood that various
modifications can be made by one skilled in the art without
departing from the scope of the present invention as defined in the
following claims.
[0043] It is therefore intended that the foregoing detailed
description be regarded as illustrative rather than limiting, and
that it be understood that it is the following claims, including
all equivalents, that are intended to define the spirit and scope
of this invention.
[0044] It is therefore intended that the foregoing detailed
description be regarded as illustrative rather than limiting, and
that it be understood that it is the following claims, including
all equivalents, that are intended to define the spirit and scope
of this invention.
* * * * *